There's a scene where Pop is taking her first trip alone and doesn't make it to the restroom in time. Fortunately, Doremi is watching from the shadows and conjures a magical washing machine (the scene ignores the fact that Pop's legs would need washing too...)
In another episode, Doremi's fairy Dodo wets the bed. Doremi is blamed for it.
In an episode of Naisho, Pop wonders what it is like to be Hana, and the two switch bodies. When Hana is in Pop's body, Doremi excuses her out, and then Hana (who is in Pop's body) wets herself.
In Naruto, the title character in a half hour special has diarrhea and every time he has a chance to go he is interrupted by someone or something — eventually at the end he just lets it go.
After failing to get away from Broly long enough to go to the washroom in the Dragon Ball Z Movie Broly: Second Coming Trunks is captured by Broly and is unable to hold it any more.
Bulma pees herself in the first episode of the original series, right after Goku rescues her from a monster that attacked her while she was trying to find privacy to pee in the first place. The same scene is in the manga.
In Sailor Moon, Chibiusa wets the bed at one point. Since she was sleeping in the same bed as Usagi that time, Usagi had to clean it up and Shingo teased her for it. This also triggers a flashback in which Chibiusa recalls how she once wet her bed at home in Crystal Tokyo and expected to be punished, but her mother Usagi's adult self aka Neo Queen Serenity comforted her instead.
The bed-wetting was cut out from the English Dub, though when Serena is airing out her mattress, you can still see a wet spot.
A BleachOmake has Vice-Captain Tetsuzaemon Iba desperately needing to use the bathroom. His captain (an anthropomorphic wolf) directs him to the bathroom from where he just came from, but when Tetsuzaemon sees a dog peeing on a post, he immediately assumes that was what his captain was talking about and runs out of time. The actual human bathroom was in fact next to the post.
Chi's Sweet Home has preschooler Yohei having an accident at the same time his mother is litter training Chi. Chi herself simply fails at first to grasp that her litter box is just that.
Subverted in a chapter of Ichinensei Ni Nacchattara, Iori (a seventeen year old boy in the body of a seven year-oldgirl), falls asleep in class and wakes up wet. He freaks and has to work up the guts to confess this fact to the teacher. Only after he does so is it learned he never wet himself at all, merely fell asleep under a leaky sprinkler nozzle.
An early chapter of Bunny Drop focused on a developing case of bedwetting by six year old Rin. While a good part of it had to do with stress from her recent issues, Rin also confessed that she was scared to get up and go to the bathroom at night by herself. In that same chapter, Daikichi admitted to having done it off and on until fourth grade.
In Girls Bravo Fukuyama blackmails Kirie into competing in his all girls fighting tournament with an embarrassing picture of her from when she was little.
Suneo of Doraemon is a bedwetter and has to wear diapers to bed.
In Kamen no Maid Guy, Liz wets her bed after having a nightmare about Kogarashi and his crows. It's later implied that these nightmares are recurring, when she shows up at a shrine looking for a way to stop it from happening.
Nana To Kaoru. She held out as long as she could, but this eventually happened to Tachi the first time she participated in one of Nana & Kaoru's bondage-based "breathers". Kaouru, being Kaouru, actually planned for that to happen by giving her lemonade beforehand and even bound her on a sheet to prevent damaging the floor.
There was once this was humorously applied in Detective Conan: Eri got Kogoro Bound and Gagged on his sofa, and while Eri was out with Ran and Conan, Kogoro complained about Potty Emergency... When they came back, they noticed a strange smell from the sofa, which Kogoro said was "dog pee."
Not actual bedwetting, but there was one early time when Nabiki dumped cold water on Ranma while he was sleeping so she could take pictures of his girl form (to sell them among the boys at schools), then she dumps warm water on Ranma to turn her back into a boy. Hilarity Ensues when Ranma, who surprisingly slept through all that, wakes up after a short while... and thinks he did wet the bed.
Implied at the end of episode 8 of Sora No Woto. Kanata suffered a Potty Emergency while having to wait for a phone call, when someone finally relieves her so she can relieve herself, she runs into Noel, is knocked to the ground and knows she's doomed if she tries to move. Cue Filicia and Kureha arriving in time to see her in distress and help her up to her feet.
In Axis Powers Hetalia, England is fast asleep at one of the meetings. In his dream, he flashes back to when America was little, scolding him for wetting the bed again.
Spain also had this problem with Romano, due to the latter not being able to find the toilet in time in Spain's Big Fancy House.
A minor one happens in Mahou Sensei Negima!, when the group ends up high in the air. After somewhat safe landing Konoka jokes how she almost wet herself... right next to clearly embarrassed Yue.
Happens a few times in Berserk. It's justifiable for the most part, since if you were faced with any one of the Eldritch Abominations presented in the series, you'd piss yourself too. However, there was one part that was Played for Laughs, while Guts was fighting some snow demons to protect Casca and she left his protective grasp. After it was over, he wondered why she went away so suddenly... Turned out she picked a great time to go number one.
Frequently happens to Mikan in Go! Go! Itsutsugo Land. After Kinoko inadvertently caused her to wet herself in kindergarten, Mikan spends the second half of the series trying to put Kinoko in situations of both artificial wetness and genuine wetness. Her plans inevitably backfire, causing her more embarrassment than what she had started with. The dub censors any wetting and changes the embarrassing fact to, "spilling juice on herself," which to be fair she actually does on more than one occasion.
The rare Played for Drama example happens in Mawaru-Penguindrum, when a not-older-than-five-years-old Ringo gets up to ask either Mom or Dad to help her go to the bathroom... and walks on them having a fight. As she watches them verbally discuss about her dead sister Momoka, little Ringo quietly pees herself while standing.
Johnny the Homicidal Maniac has this in one of the Meanwhile's (Although due to the Director's Cut, only containing the plot related stuff, you'll now find it in Squee's Wonderful Big Giant Book of Unspeakable Horrors), where a woman has a date with someone who suffers an extreme Potty Failure.
Taken to literally insane extremes by Maxie Zeus - he strews his stool around, convinced he is fertilizing the barren Earth. In the context of his particular delusion (He thinks he is God) it is in fact a sacred act. Holy shit, Batman!
Before that, Two-Face pees himself because trying to make a decision on whether to go to the bathroom using tarot cards takes a very long time.
National Lampoon's Van Wilder, when Gwen Pearson puts "Colon Blow" into Richard Bagg's drink. Though technically its not quite a failure. He ends up using a trash can, in front of his professor and (not likely after this) future boss.
In Dumb And Dumberer When Harry Met Lloyd. Harry suffers from a Potty Emergency and rushes to the bathroom. He then digs into his pants, pulls something brown and slimy out, and eats it. It turns out to be a melted chocolate bar. Which he then proceeds to smear on every surface in the bathroom, leading to this:
Jessica's Dad: Oh, my God. He shit everywhere. There's shit everywhere! Dammit! There's shit on the windows! Oh, my God! My house is full of shit! He shit everywhere! Look what he did! He shit all over the walls! There's shit everywhere!
In the first movie, Harry wets himself while he and Lloyd are riding their Moped to the ski resort. Lloyd seems to appreciate this, since it was cold.
In the Christian movie Tribulation from the Apocalypse film series, young Calvin Canboro wets his pants while he and his brother Tom wait for their sister Eileen to finish her prayer to God about the tree she carved their names into. Years later, Calvin can Never Live It Down.
This happens to the bride from Bridesmaids who takes a dump, in the middle of a street, after they all contract food poisoning. Made worse by the fact that she was trying on an expensive wedding dress at the time.
Billy Madison: Billy helps a classmate who peed in his pants by saying that is what cool people do.
In Miss March, the main character has recently gotten out of a coma, so a lot of his muscles have atrophied, including the ones that let him hold it in.
Played for Drama in Five Fingers. The main character has been captured and brutally tortured by terrorists. In the middle of the night, the man (who is heavily restrained) shouts that he has to use the bathroom, but no one is there, so he soils himself. The next morning, his captors angrily strip him naked and force him to clean himself up.
Live Action TV
There was The Young Ones episode where Rik tried to commit suicide by overdosing on pills, not realising that pills in question were laxatives. Hilarity Ensues.
Neil: Vyvyan,can you actually kill yourself with laxative pills?
Vyvyan: I dunno Neil,but I'm gonna stick around to find out!
There's an episode of Friends which ends with Joey having a Potty Failure whilst a famous director is hugging him. It's a long story. The gist of it was during his auditions, Joey noticed that he seemed to do better when he really had to go to the bathroom, thus every time he went to auditions, he'd make sure he had to go and hold it in so his performance wouldn't falter. As stated above, Joey pushed his luck and suffered wet pants when the director hugged him.
In an episode of Hollyoaks, India eats a pizza that Hayley has laced with laxatives. This leads to her winning the contest for Josh's car when she has an accident and causes everyone else to flee in disgust.
Tommy Gavin's father from Rescue Me suffered from bed wetting in Season 3.
Subverted in House when a patient tells a few doctors that he accidentally wet the bed. When then turn him over to look at his sheets, they're shocked to find out that he was really bleeding out of his ass.
In an early ER episode, Benton asks his girlfriend to look after his aging mother for a night, and she chews him out the next morning for not warning her that the old woman suffers from incontinence.
Justified in Bear In The Big Blue House episode "When You've Gotta Go." Ojo has an accident and Bear cleans up, telling her that accidents happen to everyone.
Twice in Degrassi's tenth season. The first by Jenna, who's been abusing diet pills; the second, by Holly J., who ignores what she believes to be Definitely Just a Cold. It isn't definitely just a cold.
A girl on MTV's Next wet her pants - and left her entire chair dripping - during a date, because she really had to go already but was given no opportunity to pee once she was called off the Next Bus. She was Nexted for this.
Number 32 on VH1's100 Most Shocking Moments in Music: when Fergie wet her pants on stage at the San Diego Street Scene concert.
On Law & Order: UK, when Ronnie Brooks' corrupt ex-partner blasts him for turning him in, he cites the many favors he'd done to cover for Ronnie during his drinking days, including, "loaned you a pair of trousers when you'd pissed your own".
On United States Of Tara, Tara's dad thinks he is wetting the bed, but they find out that one of her alters, Gimme, (aka the poncho goblin) was sneaking in at night and peeing on him.
One Crank Yankers sketch involves the mentally handicapped character "Special Ed" tearfully phoning a health club to apologize for peeing in the pool. The manager acknowledges his apology, and kindly reassures him that it's okay...which prompts Ed to happily shout, "I peed in your pool! YAAAAAAYYY!" repeatedly.
A demon from Angel to Fred: "My feelings for you are changing. I feel... warmth. Wait, no I don't. That's just me wetting myself because you wouldn't let me pee!"
King Boz from the Disney show Pair Of Kings wets himself in the episode "Wet Hot Kinkowan Summer."
Monty Python's Flying Circus in the "Visitors" sketch, since the uncouth crowd gathering at Victor's apartment weren't disgusting enough, Mrs. Equatol (Terry Jones), during a frequent shrieking laughing fit, declares "Oh. I wet 'em!"
On Awkward., Tamara wets her pants in the episode "My Love Is A Black Heart."
The song "Ranchera" by Chilean group Fiskales Ad Hoc is about a guy who pisses in his pants and can't go to the bathroom to, uhm, "evacuate" the rest since he's stuck with his Girl of the Week.
Actually averted in the song "Mi agüita amarilla" ("My yellow water") by Spanish group Los Toreros Muertos. It's not about a guy leaking his "yellow water" like this, and more about a guy who's bored while peeing and tries to imagine where does the pee go.
Da Yoopers' song "Diarrhea" is an apology for why the singer has to break his date. He thought that "it was only gas..." By the end, he's come up with a scheme to stop it.
In The Sims, if your Sims don't get sent to the bathroom quickly enough, they leave puddles, and their stats crash from the embarrassment. This is one method of torturing Sims. And it sometimes happens without the Potty Emergency coming first, if a Sim is subjected to Extreme Tickling.
The objective in one level of Parappa The Rapper is to prevent one of these. Do badly and it starts raining. Do well and a toilet starts chasing you. Fail the level and a cutscene shows a rocket taking off inside the titular Rapper.
Being based off its own virtual pet toy, the first Digimon World includes pooping as a factor the tamer has to take care of. Not getting in time to a nearby toilet will end up with the Digimon leaving a stool in place. Enough accidents and the Digimon will turn into a Sukamon as punishment.
During the Horde quest in Silverpine Forest in World of Warcraft, you have to pour booze over some orc sea dogs who got whooped in battle for being stone cold sober. Sometimes they will say, "I may or may not have pissed myself."
The priest who took care of Kylier from Yggdra Union mentions that she was a bed-wetter as a child.
The patient whose blood you need in the No Mercy level in PAYDAY The Heist soils himself all over the bed after several vials of blood are drawn from him. Since he is infected with an unknown disease, it's presumed he has no control over his bodily functions because of it.
Gabe: Well, you used to roll with Doobie Howser back in the day.
Tycho: Yeah, and you used to wear your pants backwards like Kris Kross. Are you an expert at making people "Jump, Jump"?
Gabe: I only did that once.
Tycho: Why only once?
[Cuts to a flashback of Gabe in high school, standing next to a urinal, with his pants soaked in urine]
Lupis from the rebooted Darwin's Soldiers Furtopia RP occasionally wets himself and spends a fair portion of the RP in diapers. Justified by the fact that he is four years old and not fully toilet trained.
Strong Sad has been hinted to wet the bed a number of times, mainly from Strong Bad.
Strong Bad himself is also hinted to do this in the Sbemail "road trip".
Also, "Halloween Potion-ma-jig" has "The Essence of Putting Strong Mad's Hand in Warm Water While He's Asleep.
Justified in Rugrats; Chuckie and Angelica (who has one when Chuckie goes to the bathroom properly for the first time) are at normal potty age, so it's natural to have at least one accident. Lou does mention that Stu took a lot longer, though.
The Powerpuff Girls episode "Pee Pee G's" had the girls freaked at the possibility that one of them is wetting the bed. This is subverted somewhat in that the answer is none of them: it was Mojo Jojo sneaking in during the night and pouring a bottle of water on the bed to screw with the girls' heads. However, when confronted, Mojo finds it so hilarious that he laughs until he "breaks his water bottle."
Bubbles, however, was confirmed to have been a bedwetter by the Professor in "Powerprof."
Patrick also has one in the episode "Snowball Effect", though it's a Downplayed example. Patrick asks Squidward to use use his bathroom; eventually, Squidward gives in, but Patrick already went.
An episode of KaBlam! had the hosts Henry and June as astronauts in spacesuits. Henry commented that he needed to use the bathroom and June asks why he doesn't just do what she did: Use her spacesuit like a real astronaut. June runs off embarrassed when Henry informs her that they aren't wearing real spacesuits, merely cheap Halloween costumes.
Henry:I think June just went where no cartoon character has gone before. In her pants!
In one "Sniz and Fondue" short, Fondue is addicted to Solitaire on the computer. He comments that he needs to tinkle, but continues to play. He soon notes he no longer has to go.
It happens The Venture Brothers when Doctor Venture is informed that the spacesuits they were wearing did not, in fact, have a waste containment system.
Pingu often found himself surrounded by a telling yellow puddle. Oops.
In Dan Vs. "Traffic," Dan swears revenge on traffic in general, after various traffic jams keep him from getting home in time, if you know what I mean.
In Home Movies, Brendon keeps good-naturedly mocking classmate Junior Ahlberg, then gets karmic payback at the end of the show when a 'funny home video' show makes a big hit of his mom's tape where a younger Brendon sings and then wets himself. It gets shown repeatedly on the evening news.
Homer, trying to make Bart look happy on the Jumbotron, tickles him. Big mistake.
In another episode, Homer gets a chronic bedwetting problem, which he spends the whole episode trying to cure.
On the ride home from an apple orchard.
Marge: Careful of the apple pie on the seat. Grandpa Simpson: Uh oh! Marge: Grandpa are you sitting on the pie? Grandpa Simpson: I sure hope so.
"Treehouse of Horror III"
Bart: I've got a story so scary you'll wet your pants!. Grandpa: Too late.
Ralph Wiggum on an ocassional basis. Most notably in "Little Girl in the Big Ten".
American Dad: In "An Incident At Owl Creek", Stan dines on a particularly greasy brisket at a neighbour's pool party, feels the urge to poop, and attempts a cannonball into the pool. Do the math. An interesting side note: the ensuing Failure is actually the kickoff point for the rest of the episode.
In one episode, Harold gets up to make fun of Phoebe for a previous incident in which she accidentally farted into a microphone in front of the whole school. Ironically, Harold ends up wetting his pants in front of the whole school, right after making fun of her.
Another episode has Olga telling Helga's classmates an "inspirational" story about a little girl who wet the bed until she was seven-years-old and strived to overcome her problem. Eventually succeeding with only one or two little accidents. The kids are soon able to figure out that the girl in the story is actually Helga.
The episode "World Wide Recorder Concert" features the Brown Noise which, when heard, causes a person to lose control of their bowels. The boys slip this into the sheet music of rivals, but it accidentally gets added to the sheet music for the entire concert, which is being broadcast worldwide...
Reporter: Like the rest of the world, everyone here has crapped their pants. Some crapped themselves to death. And still others ...ruined perfectly good pairs of pants.
"Bass To Mouth" combines this with Laxative Prank. The school staff tells Cartman they want him to ensure Pete Melman won't kill himself like a previous student did after being ridiculed for crapping his pants. His solution is to give Jenny Simon a laxative-laced cupcake; Cartman figures this will guarantee that attention is diverted from Melman, but now Jenny ends up attempting suicide. Cartman decides to fix everything by having all the students eat pizza with laxatives so no one gets singled out.
In "I Should Have Never Gone Ziplining", Cartman gets diarrhea from the tacos he ate earlier, and shits his pants.
Kyle: Dude, did you just shit your pants?
Bobs Burgers had one episode where Bob gets knocked down to the floor and lands on his ass, resulting in him soiling himself in front of everyone.
In the episode "Brian in Love", Brian suffers from this problem.
In "The Splendid Source", Peter craps his pants every time he hears a joke that Joe and Quagmire recently learned about, which the two then decide to tell it every single time to Peter just to prank him so he keeps soiling himself. It stops when Peter tries to get revenge by wearing Quagmire's pants and awaits the joke, causing Quagmire to stop.
One quickie shown during an episode of Garfield and Friends had Jon mistake Odie's drool beside Garfield's bed for pee. Due to this, Jon puts Garfield in a diaper, and then Garfield diapers Odie's mouth.